Future reduction of sea ice in the Arctic could result in a loss of 2/3
of the world’s polar bear population within 50 years according to a
series of studies released today by the U.S. Geological Survey.

Last December, Secretary of the Interior Dirk Kempthorne announced that
the U.S. Fish and Wildlife Service (Service) was proposing to list the polar
bear as a threatened species under the Endangered Species Act. In January
2008, following a one-year review period, the Service is expected to make
a recommendation to Secretary Kempthorne on whether or not to list the polar
bear as threatened. To assist the Service in making that recommendation,
Secretary Kempthorne requested USGS leadership in studies to inform the Service’s
deliberations on polar bear status. This information summarizes and integrates
the results from a series of studies on polar bear populations, range-wide
habitats and changing sea ice conditions in the Arctic.

In making the announcement last December, Secretary Kempthorne said: “I
am directing the U.S. Fish and Wildlife Service and the U.S. Geological Survey
to aggressively work with the public and the scientific community over the
next year to broaden our understanding of what is happening with the species.
This information will be vital to the ultimate decision on whether the species
should be listed.”

Specifically the USGS has improved knowledge on the status of three polar
bear sub-populations, projected numbers of polar bears into the future in
relation to sea ice and integrated the information into a range-wide assessment
of polar bear status under scenarios of future climate change.

The newly-released USGS information, presented to the Service in the form
of nine administrative reports to be open for public comment, will now be
considered within the context of the Service’s one-year review. The
Service will analyze it and other information provided by scientists, government
agencies and the public in order to arrive at an informed and scientifically
justifiable decision. That decision is due in January.

The team investigating the future of polar bears and their habitat included
scientists from the USGS, other American and Canadian government agencies,
academia and the private sector.

“This team has done a tremendous job in furthering polar bear science
through the use of long-term observational measurements on polar bears, their
habitats, and many other factors integrated into a range of new and traditional
models,” said Mark Myers, Director of the U.S. Geological Survey.

During a six-month period of intensive analysis of both existing and new
data, the team documented the direct relationship between the presence of
Arctic sea ice and the survival and health of polar bears. Polar bears depend
on sea ice as a platform to hunt seals, their primary food. But sea ice is
decreasing throughout their Arctic range due to climate change. Models used
by the USGS team project a 42 percent loss of optimal polar bear habitat
from the Polar Basin during summer, a vital hunting and breeding period,
by mid-century.

In addition to forecasts, declines in habitat have been recorded throughout
the Polar Basin over the past 20 years of observations. To project future
sea ice conditions, USGS scientists used 10 general circulation models that
best approximated observed trends in sea-ice loss and could be expected to
do the best job of simulating future conditions. Scientists characterize
their conclusions as conservative because even the best available models
are believed to underestimate the actual decline in Arctic sea ice.